Caretaker views on deep brain stimulation for cognitively impaired patients with Parkinson's disease

Neuropsychological assessment is crucial in the presurgical evaluation of patients with Parkinson's disease (PD) who are contemplating deep-brain stimulation (DBS). No standardized screening test battery currently exists. Our movement disorder group most frequently employs the Mattis dementia rating scale (MDRS) and usually advises against DBS for PD patients with MDRS ≤130. We reviewed patient-reported outcomes and satisfaction with DBS in these borderline patients.

We retrospectively reviewed a single-center database of 696 DBS patients to identify individuals with PD and an MDRS score ≤130. Telephone interviews were conducted with the patient's primary caretaker (PCT) to assess long-term satisfaction with the procedure. Electronic medical records were reviewed to analyze patient demographics, preoperative assessments, and surgical complications.

We identified 19 DBS patients and interviewed 6 PCTs. Five (83%) PCTs reported they were "very satisfied" with long-term DBS outcomes, and one (17%) reported they were "satisfied." All PCTs reported improved patient quality of life and motor symptoms, would urge their loved one to undergo surgery again, and have recommended DBS surgery to others. Three PCTs reported eventual worsened cognition, while one reported improved cognition.

A MDRS score ≤130 by itself does not preclude a poor outcome with DBS for PD. A standardized battery of preoperative neuropsychological testing for DBS is needed to establish better evidenced-based "cutoff " scores and to improve candidate selection.